BACKGROUND: Extreme temperature events, including extreme cold, are becoming more frequent worldwide, which might be harmful to pregnant women and cause adverse birth outcomes. We aimed to investigate the association between exposure to low ambient temperature in pregnant women and adverse birth outcomes, such as preterm birth, low birth weight, and stillbirth, and to summarize the evidence herein. METHODS: Relevant studies were searched in PubMed, Cochrane, and Embase electronic databases until November 2021. Studies involving low ambient temperature, preterm birth, birth weight, and stillbirth were included. The guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses were followed to conduct this study risk of bias and methods for data synthesis. RESULTS: A total of 34 studies were included. First, pregnant women exposed to low ambient temperature had an increased risk of preterm birth (risk ratio [RR] 1.08; 95% confidence interval [CI] 1.04-1.13). Subgroup analyses revealed that exposure during late pregnancy was more likely to induce preterm birth. In addition, only pregnant women exposed to <1st percentile of the mean temperature suffered increased risk of preterm birth. Moreover, pregnant women living in medium or hot areas were more prone to have preterm births than those in cold areas when exposed to low ambient temperatures. Asians and Blacks were more susceptible to low ambient temperatures than Caucasians. Second, pregnant women exposed to low ambient temperature had an increased risk of low birth weight (RR 1.07; 95% CI 1.03-1.12). Third, pregnant women had an increased risk of stillbirth while exposed to low ambient temperature during the entire pregnancy (RR 4.63; 95% CI 3.99-5.38). CONCLUSIONS: Exposure to low ambient temperature during pregnancy increases the risk of adverse birth outcomes. Pregnant women should avoid exposure to extremely low ambient temperature (<1st percentile of the mean temperature), especially in their late pregnancy. This study could provide clues for preventing adverse outcomes from meteorological factors. REGISTRATION No. CRD42021259776 at PROSPERO ( https://www.crd.york.ac.uk/PROSPERO/ ).
Pregnancy ; Infant, Newborn ; Female ; Humans ; Pregnancy Outcome ; Premature Birth/epidemiology* ; Stillbirth/epidemiology* ; Temperature ; Pregnancy Complications

OBJECTIVES: To explore the association between assisted reproductive technology (ART) and birth weight discordance in twins (BWDT). METHODS: A retrospective analysis was conducted on twin infants born between January 2011 and December 2020 at the Third Affiliated Hospital of Guangzhou Medical University, with complete basic birth data. The impact of ART on the occurrence of BWDT was identified by the multivariate logistic regression analysis. RESULTS: A total of 3 974 pairs of twins were included, with 1 431 conceived naturally and 2 543 through ART. Neonates in the ART group had higher birth weights than those in the naturally conceived group (P<0.001). The incidence of BWDT was lower in the ART group compared to the naturally conceived group (16.17% vs 21.09%, P<0.001). The multivariate logistic regression analysis, adjusting for confounding factors such as maternal age, parity, pre-pregnancy body mass index, gestational diabetes, hypothyroidism, gestational age, and chorionic properties, showed no significant difference in the risk of BWDT between the ART and naturally conceived groups (P>0.05). CONCLUSIONS ART is not associated with the risk of BWDT.
Pregnancy ; Infant, Newborn ; Female ; Humans ; Birth Weight ; Pregnancy Outcome ; Infant, Premature ; Infant, Low Birth Weight ; Pregnancy, Multiple ; Premature Birth/epidemiology* ; Retrospective Studies ; Population Surveillance ; Reproductive Techniques, Assisted/adverse effects* ; Pregnancy Complications

Objective: To analyze the prevalence and the risk factors of fungal sepsis in 25 neonatal intensive care units (NICU) among preterm infants in China, and to provide a basis for preventive strategies of fungal sepsis. Methods: This was a second-analysis of the data from the "reduction of infection in neonatal intensive care units using the evidence-based practice for improving quality" study. The current status of fungal sepsis of the 24 731 preterm infants with the gestational age of <34⁺⁰ weeks, who were admitted to 25 participating NICU within 7 days of birth between May 2015 and April 2018 were retrospectively analyzed. These preterm infants were divided into the fungal sepsis group and the without fungal sepsis group according to whether they developed fungal sepsis to analyze the incidences and the microbiology of fungal sepsis. Chi-square test was used to compare the incidences of fungal sepsis in preterm infants with different gestational ages and birth weights and in different NICU. Multivariate Logistic regression analysis was used to study the outcomes of preterm infants with fungal sepsis, which were further compared with those of preterm infants without fungal sepsis. The 144 preterm infants in the fungal sepsis group were matched with 288 preterm infants in the non-fungal sepsis group by propensity score-matched method. Univariate and multivariate Logistic regression analysis were used to analyze the risk factors of fungal sepsis. Results: In all, 166 (0.7%) of the 24 731 preterm infants developed fungal sepsis, with the gestational age of (29.7±2.0) weeks and the birth weight of (1 300±293) g. The incidence of fungal sepsis increased with decreasing gestational age and birth weight (both P<0.001). The preterm infants with gestational age of <32 weeks accounted for 87.3% (145/166). The incidence of fungal sepsis was 1.0% (117/11 438) in very preterm infants and 2.0% (28/1 401) in extremely preterm infants, and was 1.3% (103/8 060) in very low birth weight infants and 1.7% (21/1 211) in extremely low birth weight infants, respectively. There was no fungal sepsis in 3 NICU, and the incidences in the other 22 NICU ranged from 0.7% (10/1 397) to 2.9% (21/724), with significant statistical difference (P<0.001). The pathogens were mainly Candida (150/166, 90.4%), including 59 cases of Candida albicans and 91 cases of non-Candida albicans, of which Candida parapsilosis was the most common (41 cases). Fungal sepsis was independently associated with increased risk of moderate to severe bronchopulmonary dysplasia (BPD) (adjusted OR 1.52, 95%CI 1.04-2.22, P=0.030) and severe retinopathy of prematurity (ROP) (adjusted OR 2.55, 95%CI 1.12-5.80, P=0.025). Previous broad spectrum antibiotics exposure (adjusted OR=2.50, 95%CI 1.50-4.17, P<0.001), prolonged use of central line (adjusted OR=1.05, 95%CI 1.03-1.08, P<0.001) and previous total parenteral nutrition (TPN) duration (adjusted OR=1.04, 95%CI 1.02-1.06, P<0.001) were all independently associated with increasing risk of fungal sepsis. Conclusions: Candida albicans and Candida parapsilosis are the main pathogens of fungal sepsis among preterm infants in Chinese NICU. Preterm infants with fungal sepsis are at increased risk of moderate to severe BPD and severe ROP. Previous broad spectrum antibiotics exposure, prolonged use of central line and prolonged duration of TPN will increase the risk of fungal sepsis. Ongoing initiatives are needed to reduce fungal sepsis based on these risk factors.
Infant ; Infant, Newborn ; Humans ; Birth Weight ; Intensive Care Units, Neonatal ; Retrospective Studies ; Tertiary Care Centers ; Infant, Extremely Low Birth Weight ; Gestational Age ; Infant, Extremely Premature ; Sepsis/epidemiology* ; Retinopathy of Prematurity/epidemiology* ; Bronchopulmonary Dysplasia/epidemiology*

Objective: To investigate the prevalence and poor prognosis of late-onset sepsis (LOS) in very low birth weight infant (VLBWI). Methods: This prospective, multicenter observational cohort study was conducted based on the data from Sina-Northern Neonatal Network (SNN). The general data, perinatal information and poor prognosis of 6 639 VLBWI, who were admitted to the 35 neonatal intensive care units from 2018 to 2021, were collected and analyzed. According to the occurrence of LOS during hospitalization, the VLBWI were assigned to the LOS group and non-LOS group. The LOS group was further divided into 3 subgroups according to the occurrence of neonatal necrotizing enterocolitis (NEC) and purulent meningitis. The Chi-square test or Fisher exact probability method, independent sample t test, Mann-Whitney U test and multivariate Logistic regression model were used to analyze the relationship between LOS and poor prognosis in VLBWI. Results: A total of 6 639 eligible VLBWI were enrolled, including 3 402 cases (51.2%) of males and 1 511 cases (22.8%) with LOS. The incidences of LOS in extremely low birth weight infants (ELBWI) and extremely preterm infants were 33.3% (392/1 176) and 34.2% (378/1 105), respectively. There were 157 cases (10.4%) who died in the LOS group and 48 cases (24.9%) in the subgroup of LOS complicated with NEC. Multivariate Logistic regression analysis showed that LOS complicated with NEC was associated with increased mortality and incidence of grade Ⅲ-Ⅳ intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL), moderate or severe bronchopulmonary dysplasia (BPD), and extrauterin growth retardation (EUGR) (OR_adjust=5.27, 2.59, 3.04, 2.04; 95%CI 3.60-7.73, 1.49-4.50, 2.11-4.37, 1.50-2.79; all P<0.01); LOS complicated with purulent meningitis was also associated with increased mortality and incidence of grade Ⅲ-Ⅳ IVH or PVL, and moderate or severe BPD (OR_adjust=2.22, 8.13, 3.69, 95%CI 1.30-3.37, 5.22-12.67, 2.49-5.48; all P<0.01); the infants without NEC or purulent meningitis in the LOS group was only associated with increased incidence of moderate or severe BPD (OR_adjust=2.20, 95%CI 1.83-2.65, P<0.001). After ruling out contaminated bacteria, a total of 456 cases showed positive blood culture, including 265 cases (58.1%) of Gram-negative bacteria, 126 cases (27.6%) of Gram-positive bacteria, and 65 cases (14.3%) of fungi. The most common pathogenic bacteria was Klebsiella pneumoniae (n=147, 32.2%), followed by coagulase-negative Staphylococcus (n=72, 15.8%) and subsequently Escherichia coli (n=39, 8.6%). Conclusions: The incidence of LOS is high in VLBWI. Klebsiella pneumoniae is the most common pathogenic bacteria, followed by coagulase-negative Staphylococcus and Escherichia coli. LOS is associated with a poor prognosis for moderate to severe BPD. The prognosis of LOS complicated with NEC is poor with the highest mortality, and the risk of brain damage is significantly increased when LOS complicated with purulent meningitis.
Infant ; Male ; Female ; Pregnancy ; Infant, Newborn ; Humans ; Prospective Studies ; Coagulase ; Infant, Extremely Low Birth Weight ; Sepsis/epidemiology* ; Bronchopulmonary Dysplasia ; Escherichia coli ; Infant, Extremely Premature ; Meningitis

Systemic lupus erythematosus (SLE) is an autoimmune connective tissue disease that affects multiple organs and systems. It is more common in women of childbearing age. Compared with the general population, pregnant women with SLE are at a significantly increased risk of adverse perinatal outcomes such as preterm birth and intrauterine growth restriction. In addition, the offspring of SLE patients may also be adversely affected by in utero exposure to maternal autoantibodies, cytokines, and drugs. This article summarizes the long-term developmental outcomes of offspring of pregnant women with SLE in terms of the blood system, circulatory system, nervous system, and immune system.
Pregnancy ; Humans ; Female ; Infant, Newborn ; Pregnancy Outcome/epidemiology* ; Pregnant Women ; Pregnancy Complications/epidemiology* ; Premature Birth/etiology* ; Lupus Erythematosus, Systemic

Objective: To investigate the clinical characteristics and the risk factors of severe human metapneumovirus (hMPV)-associated community acquired pneumonia (CAP) in children. Methods: A retrospective case summary was conducted. From December 2020 to March 2022, 721 children who were diagnosed with CAP and tested positive for hMPV nucleic acid by PCR-capillary electrophoresis fragment analysis of nasopharyngeal secretions at the Yuying Children's Hospital, the Second Affiliated Hospital of Wenzhou Medical University were selected as the research objects. The clinical characteristics, epidemiological characteristics and mixed pathogens of the two groups were analyzed. According to CAP diagnostic criteria, the children were divided into the severe group and the mild group. Chi-square test or Mann-Whitney rank and contrast analysis was used for comparison between groups, while multivariate Logistic regression was applied to analyze the risk factors of the severe hMPV-associated CAP. Results: A total of 721 children who were diagnosed with hMPV-associated CAP were included in this study, with 397 males and 324 females. There were 154 cases in the severe group. The age of onset was 1.0 (0.9, 3.0) years, <3 years old 104 cases (67.5%), and the length of hospital stay was 7 (6, 9) days. In the severe group, 67 children (43.5%) were complicated with underlying diseases. In the severe group, 154 cases (100.0%) had cough, 148 cases (96.1%) had shortness of breath and pulmonary moist rales, and 132 cases (85.7%) had fever, 23 cases (14.9%) were complicated with respiratory failure. C-reactive protein (CRP) was elevated in 86 children (55.8%), including CRP≥50 mg/L in 33 children (21.4%). Co-infection was detected in 77 cases (50.0%) and 102 strains of pathogen were detected, 25 strains of rhinovirus, 17 strains of Mycoplasma pneumoniae, 15 strains of Streptococcus pneumoniae, 12 strains of Haemophilus influenzae and 10 strains of respiratory syncytial virus were detected. Six cases (3.9%) received heated and humidified high flow nasal cannula oxygen therapy, 15 cases (9.7%) were admitted to intensive care unit, and 2 cases (1.3%) received mechanical ventilation. In the severe group, 108 children were cured, 42 children were improved, 4 chlidren were discharged automatically without recovery and no death occurred. There were 567 cases in the mild group. The age of onset was 2.7 (1.0, 4.0) years, and the length of hospital stay was 4 (4, 6) days.Compared with the mild group, the proportion of children who age of disease onset <6 months, CRP≥50 mg/L, the proportions of preterm birth, congenital heart disease, malnutrition, congenital airway malformation, neuromuscular disease, mixed respiratory syncytial viruses infection were higher (20 cases (13.0%) vs. 31 cases (5.5%), 32 cases (20.8%) vs. 64 cases (11.3%), 23 cases (14.9%) vs. 44 cases (7.8%), 11 cases (7.1%) vs. 18 cases (3.2%), 9 cases (5.8%) vs. 6 cases (1.1%), 11 cases (7.1%) vs. 12 cases (2.1%), 8 cases (5.2%) vs. 4 cases (0.7%), 10 cases (6.5%) vs. 13 cases (2.3%), χ²=0.42, 9.45, 7.40, 4.94, 11.40, 8.35, 3.52, 6.92, all P<0.05). Multivariate Logistic regression analysis showed that age<6 months (OR=2.51, 95%CI 1.29-4.89), CRP≥50 mg/L (OR=2.20, 95%CI 1.36-3.57), prematurity (OR=2.19, 95%CI 1.26-3.81), malnutrition (OR=6.05, 95%CI 1.89-19.39) were the independent risk factors for severe hMPV-associated CAP. Conclusions: Severe hMPV-associated CAP is most likely to occur in infants under 3 years old and has a higher proportion of underlying diseases and co-infection. The main clinical manifestations are cough, shortness of breath and pulmonary moist rales, fever. The overall prognosis is good. Age<6 months, CRP≥50 mg/L, preterm birth, malnutrition are the independent risk factors for severe hMPV-associated CAP.
Infant ; Male ; Female ; Humans ; Child ; Infant, Newborn ; Child, Preschool ; Retrospective Studies ; Cough ; Coinfection ; Premature Birth ; Respiratory Sounds ; Metapneumovirus ; Pneumonia, Viral/epidemiology* ; Respiratory Syncytial Virus, Human ; Community-Acquired Infections/epidemiology* ; Risk Factors ; Dyspnea ; Malnutrition

Objective: To investigate the impact of obstructive sleep apnea syndrome (OSAS) on pregnancy outcomes, especially the relationship between OSAS and hypertensive disorders in pregnancy (HDP). Methods: A total of 228 pregnant women with high risk of OSAS who underwent sleep monitoring during pregnancy in Peking University People's Hospital from January 2021 to April 2022 were collected by reviewing their medical records for retrospective analysis. According to the diagnosis of OSAS, the pregnant women were divided into OSAS group (105 cases) and non-OSAS group (123 cases). The non-parametric Mann-Whitney U test, χ² test or Fisher's exact test were used to compare the general data and maternal and fetal outcomes between the two groups, and the occurrence of each type of HDP was further compared. Results: (1) Compared with the non-OSAS group, the median pre-pregnancy body mass index (23.6 vs 27.6 kg/m²) and the proportion of snoring [28.9% (33/114) vs 59.2% (61/103)] in the OSAS group were higher, and the differences were both statistically significant (both P<0.001). (2) The incidence of HDP [67.6% (71/105) vs 39.0% (48/123)] and gestational diabetes mellitus [GDM; 40.0% (42/105) vs 26.8% (33/123)] of pregnant women in the OSAS group were higher than those in the non-OSAS group, and the median delivery week was shorter than that in the non-OSAS group (38.4 vs 39.0 weeks). The differences were all statistically significant (all P<0.05). Between-group differences for the delivery way, postpartum hemorrhage, the rate of intensive care unit admission, preterm birth, small for gestational age infants, neonatal asphyxia, the rate of neonatal intensive care unit admission, newborn birth weight and the proportion of umbilical artery blood pH<7.00 were not statistically significant (all P>0.05). (3) Compared with the non-OSAS group, the incidence of chronic hypertension [11.4% (14/123) vs 22.9% (24/105)] and chronic hypertension with superimposed pre-eclampsia [11.4% (14/123) vs 30.5% (32/105)] were higher in the OSAS group, and the differences were both statistically significant (both P<0.01). Conclusion: OSAS is related to HDP (especially chronic hypertension and chronic hypertension with superimposed pre-eclampsia) and GDM, which could provide a practical basis for the screening, diagnosis and treatment of OSAS in pregnant women at high risk.
Infant, Newborn ; Pregnancy ; Infant ; Humans ; Female ; Pre-Eclampsia/epidemiology* ; Hypertension, Pregnancy-Induced/epidemiology* ; Retrospective Studies ; Premature Birth ; Sleep Apnea, Obstructive/epidemiology* ; Diabetes, Gestational/epidemiology*

Objective: To investigate the relationship between positive anti-Ro/Sjögren syndrome antigen type A (SSA) antibody and anti-La/Sjögren syndrome antigen type B (SSB) antibody in pregnant women and neonatal adverse outcomes. Methods: This study was a retrospective study, and 145 deliveries of 136 anti-Ro/SSA and anti-La/SSB antibody positive pregnant women were selected who had prenatal examination and delivered in Peking University First Hospital from January 2017 to June 2022. According to whether adverse neonatal outcomes occurred, 145 deliveries were divided into adverse outcome group (26 cases) and no adverse outcome group (119 cases). According to the time when anti-Ro/SSA and anti-La/SSB antibodies were found positive, 145 deliveries were divided into the antibody positive during pregnancy group (69 cases) and the pre-pregnancy antibody positive group (76 cases). The pregnancy outcomes, treatment and maternal and infant antibody levels of pregnant women between the adverse outcome group and no adverse outcome group, between antibody positive during pregnancy group and the pre-pregnancy antibody positive group were compared. Results: (1) Most of the pregnant women with positive anti-Ro/SSA and anti-La/SSB antibodies were diagnosed as undifferentiated connective tissue disease, accounting for 40.4% (55/136), followed by Sjogren's syndrome (25.0%, 34/136), systemic lupus erythematosus (23.5%, 32/136), antiphospholipid antibody syndrome (6.6%, 9/136), idiopathic thrombocytopenic purpura (1.5%, 2/136), and 4 cases were not diagnosed. (2) The titers of anti-Ro/SSA and anti-La/SSB antibodies in the first trimester and the second trimester were compared, and there were no statistical significances (all P>0.05). (3) The proportion of high level anti-Ro/SSA antibody (>100 kU/L), positive level of anti-La/SSB antibody and positive rate of anti-La/SSB antibody in the adverse outcome group were higher than those in the no adverse outcome group, and the birth weight of newborns and live birth rate in the adverse outcome group were lower than that in the no adverse outcome group, all with statistical significances (all P<0.05). The anti-Ro/SSA antibody level, the proportion of drug treatment (hydroxychloroquine, glucocorticoid, gamma globulin), the incidence of fetal growth restriction (FGR), the rate of preterm birth, and the positive level of anti-Ro/SSA and anti-La/SSB antibodies in newborns were compared between the two groups, and there were no statistically significant differences (all P>0.05). (4) The anti-Ro/SSA antibody level of pregnant women in the pre-pregnancy antibody positive group, the proportion of hydroxychloroquine and glucocorticoid treatment, and the anti-Ro/SSA antibody positive rate of newborns were higher, while the incidence of FGR and gamma globulin treatment rate of newborns in the antibody positive during pregnancy group were higher, respectively, and the differences were statistically significant (all P<0.05). The levels of anti-La/SSB antibodies in pregnant women, anti-Ro/SSA and anti-La/SSB antibodies in newborns, the positive rate of anti-La/SSB antibodies in newborns and the incidence of adverse outcomes were compared between the antibody positive during pregnancy group and the pre-pregnancy antibody positive group, and there were no statistical significances (all P>0.05). Conclusions: High concentrations of anti-Ro/SSA antibodies and co-positive anti-La/SSB antibodies during pregnancy may increase the incidence of adverse neonatal outcomes. There is no significant difference in the incidence of adverse neonatal outcomes between antibody positive pregnant women and antibody positive pregnant women who were first found during pregnancy after comprehensive treatment in the rheumatology and immunology department.
Infant, Newborn ; Humans ; Female ; Pregnancy ; Sjogren's Syndrome/drug therapy* ; Pregnant Women ; Hydroxychloroquine/therapeutic use* ; Retrospective Studies ; Glucocorticoids ; Premature Birth/epidemiology* ; Lupus Erythematosus, Systemic/drug therapy* ; Pregnancy Outcome ; gamma-Globulins

Objective: To investigate the clinical characteristics and maternal and fetal prognosis of pregnant women with acute fatty liver of pregnancy (AFLP). Methods: The clinical data of 86 AFLP pregnant women admitted to the Third Affiliated Hospital of Guangzhou Medical University from September 2017 to August 2022 were collected, and their general data, clinical characteristics, laboratory tests and maternal and fetal outcomes were retrospectively analyzed. Results: (1) General information: the age of the 86 pregnant women with AFLP was (30.8±5.4) years, and the body mass index was (21.0±2.5) kg/m². There were 50 primiparas (58.1%, 50/86) and 36 multiparas (41.9%, 36/86). There were 64 singleton pregnancies (74.4%, 64/86) and 22 twin pregnancies (25.6%, 22/86). (2) Clinical characteristics: the main complaints of AFLP pregnant women were gastrointestinal symptoms, including epigastric pain (68.6%, 59/86), nausea (47.7%, 41/86), anorexia (46.5%, 40/86), vomiting (39.5%, 34/86). The main non-gastrointestinal symptoms were jaundice of skin and/or scleral (54.7%, 47/86), edema (38.4%, 33/86), fatigue (19.8%, 17/86), bleeding tendency (16.3%, 14/86), polydipsia or polyuria (14.0%, 12/86), skin itching (8.1%, 7/86), and 17.4% (15/86) AFLP pregnant women had no obvious symptoms. (3) Laboratory tests: the incidence of liver and kidney dysfunction and abnormal coagulation function in AFLP pregnant women was high, and the levels of blood ammonia, lactate dehydrogenase and lactic acid were increased, and the levels of hemoglobin, platelet and albumin decreased. However, only 24 cases (27.9%, 24/86) of AFLP pregnant women showed fatty liver by imageology examination. (4) Pregnancy outcomes: ① AFLP pregnant women had a high incidence of pregnancy complications, mainly including renal insufficiency (95.3%, 82/86), preterm birth (46.5%, 40/86), hypertensive disorders in pregnancy (30.2%, 26/86), gestational diabetes mellitus (36.0%, 31/86), fetal distress (24.4%, 21/86), pulmonary infection (23.3%, 20/86), disseminated intravascular coagulation (16.3%, 14/86), multiple organ dysfunction syndrome (16.3%, 14/86), hepatic encephalopathy (9.3%, 8/86), and intrauterine fetal death (2.3%, 2/86). ② Treatment and outcome of AFLP pregnant women: the intensive care unit transfer rate of AFLP pregnant women was 66.3% (57/86). 82 cases were improved and discharged after treatment, 2 cases were transferred to other hospitals for follow-up treatment, and 2 cases (2.3%, 2/86) died. ③ Neonatal outcomes: except for 2 cases of intrauterine death, a total of 106 neonates were delivered, including 39 cases (36.8%, 39/106) of neonatal asphyxia, 63 cases (59.4%, 63/106) of neonatal intensive care unit admission, and 3 cases (2.8%, 3/106) of neonatal death. Conclusions: AFLP is a severe obstetric complication, which is harmful to mother and fetus. In the process of clinical diagnosis and treatment, attention should be paid to the clinical manifestations and laboratory tests of pregnant women, early diagnosis and active treatment, so as to improve maternal and fetal outcomes.
Pregnancy ; Infant, Newborn ; Female ; Humans ; Adult ; Retrospective Studies ; Premature Birth/epidemiology* ; Pregnancy Complications/diagnosis* ; Fatty Liver/diagnosis* ; Fetal Death ; Stillbirth

Objective: To analyze the incidence of preterm birth based on pre-pregnancy body mass index (BMI) stratification and explore the associated factors of preterm birth among pregnant women at different BMI stratifications. Methods: From February 2018 to December 2020, pregnant women who participated in China Birth Cohort Study (CBCS) and gave birth at Beijing Obstetrics and Gynecology Hospital were enrolled as the study subjects. Electronic Data Capture System and standard structured questionnaires were used to collect data related to pre-pregnancy, pregnancy, and delivery for pregnant women. Pregnant women were divided into the low-weight group, normal-weight group and overweight group based on their pre-pregnancy BMI. A Cox proportional hazards model was used to analyze the associated factors of preterm birth among pregnant women with different BMI before pregnancy. Results: A total of 27 195 singleton pregnant women were included, with a preterm birth rate of 5.08% (1 381/27 195). The preterm birth rates in the low-weight group, normal-weight group and overweight group were 4.29% (138/3 219), 4.63% (852/18 390) and 7.00% (391/5 586) respectively (P<0.001). After adjusting for relevant factors, the Cox proportional hazards model showed that the risk of preterm birth in the overweight group was 1.457 times higher than that in the normal-weight group (95%CI: 1.292-1.643). Preeclampsia-eclampsia (HR=2.701, 95%CI: 1.318-5.537) was the associated factor for preterm birth in the low-weight group. Advanced maternal age (HR=1.232, 95%CI: 1.054-1.441), history of preterm birth (HR=4.647, 95%CI: 3.314-6.515), vaginal bleeding in early pregnancy (HR=1.613, 95%CI: 1.380-1.884), and preeclampsia-eclampsia (HR=3.553, 95%CI: 2.866-4.404) were associated factors for preterm birth in the normal-weight group. Advanced maternal age (HR=1.473, 95%CI: 1.193-1.818), history of preterm birth (HR=3.209, 95%CI: 1.960-5.253), vaginal bleeding in early pregnancy (HR=1.636, 95%CI: 1.301-2.058), preeclampsia-eclampsia (HR=2.873, 95%CI:2.265-3.643), and pre-gestational diabetes mellitus (HR=1.867, 95%CI: 1.283-2.717) were associated factors for preterm birth in the overweight group. Conclusion: Pre-pregnancy overweight is an associated factor for preterm birth, and there are significant differences in the associated factors of preterm birth among pregnant women with different BMI before pregnancy.
Pregnancy ; Infant, Newborn ; Female ; Humans ; Body Mass Index ; Overweight/epidemiology* ; Premature Birth/epidemiology* ; Pre-Eclampsia/epidemiology* ; Cohort Studies ; Eclampsia ; Incidence ; Risk Factors ; Thinness/epidemiology*